Method and apparatus for packaging in protective atmosphere



Dec.' 2, 1969 R. c. BERGSTROM 3,481,100

METHOD AND APPARATUS FOR PACKAGING IN PROTECTIVE ATMOSPHERE Filed Nov.23, 1966 3 Sheets-Sheet 1 Dec. 2, 1969 R. c. BERGSTROM 3,481,100

RATUS F0 Filed Nov. 23, 1966 3 Sheets-Sheet 2 D 2, 1969 I R. c.BERGSTROM 3,431,100

METHOD AND APPARATUS FOR PACKAGING IN PROTECTIVE ATMOSPHERE Filed Nov.23, 1966 86 3 Sheets-Sheet 5 United States Patent 3,481,100 METHOD ANDAPPARATUS FOR PACKAGING IN PROTECTIVE ATMOSPHERE Roger C. Bergstrom,Rockford, Ill., assignor to Anderson Bros. Mfg. Co., Rockford, Ill., acorporation of Illinois Filed Nov. 23, 1966, Ser. No. 596,581 Int. Cl.B65b 31/06 US. CI. 53-22 7 Claims ABSTRACT OF THE DISCLOSURE In general,the disclosure sets forth a method and apparatus for forming a containerhaving an outturned peripheral flange member, enclosing the containerand a cover member in an evacuable chamber, evacuating the chamber,introducing a protective atmosphere into the container and chamber, andsealing the cover member to the flange member. The containers are formedin a continuous sheet and, in the embodiment illustrated, an opening isformed in the flange intermediate two containers. The evacuable chamberis formed of two parts which clamp the cover member and flange member attwo opposite sides of the package and outwardly of the opening. At leastone other side is left unclamped and the chamber evacuated outwardly ofthe container with the air in the container flowing between the membersat the unclamped side and thereby being evacuated. The protectiveatmosphere is introduced through the opening, into the container, andtherefrom between the members at the unclamped side into the chamber.The cover member is thereafter hermetically sealed to the flange memberinwardly of the opening and removed from the chamber.

The present invention relates generally to packaging and moreparticularly to method and apparatus for packaging in a protectiveatmosphere.

Many products are presently marketed in packages formed by Wrappinggas-impervious sheet material around the product and exhausting air fromthe package. This is known as vacuum packaging. Food products such ascheese and meats are typical of products benefited by this type ofpackaging since it reduces the tendency of product deterioration byoxidation. More recently, the air in packages has been replaced by aninert or protective gas, e.g. nitrogen, carbon dioxide, and the like.These protective atmospheres further contribute to the preservation ofthe product. Previous methods have involved the gas flush principle inwhich the package is partially sealed and the protective gas flowed intothe package through a lancet or the like extending into the package. Thelancet is withdrawn and the end of the package is subsequently sealed.Another previous method has involved a type of vacuum packaging in whichthe air is exhausted from the package and partially replaced with aprotective atmosphere. The package is then sealed. This causes thepackage to collapse around the product when exposed to atmosphere.

It is an object of the present invention to provide a new and usefulpackaging method and apparatus having advantages of both vacuum and gasflush packaging.

Another object of this invention is to provide packaging apparatus, anda method of packaging, for evacuating and gassing a container with aprotective atmosphere.

Still another object is to provide a method and apparatus for packagingin a protective atmosphere in which a chamber surrounding the package isevacuated and the protective atmosphere is passed into the package andtherefrom in the chamber.

Yet another object of the present invention is to provide a novel methodand apparatus for packaging in a protective atmosphere in which theprotective gas is passed into the package without the use of apparatusextending into the package.

Another object is to provide a method and apparatus for packaging in aprotective atmosphere in which the FIG. 4 is a partial sectional view ofthe evacuable cham- I ber and sealing head taken generally along line 44of FIG. 5;

FIG. 5 is a partial sectional view taken generally along line 55 of FIG.4; and

FIG. 6 is a view similar to FIG. 5 but showing the sealing head insealing position.

An apparatus for performing the steps of the method is diagrammaticallyillustrated in FIG. 1. The apparatus generally is an improvement onmachines of the type disclosed in J. G. H. Ollier et a1. Patent No.3,196,590 and reference is made thereto for the disclosure of the oldstructure.

Reference is now made more particularly to the drawings which illustratethe best presently known mode of carrying out the invention and whereinsimilar reference characters indicate the same parts throughout theseveral views.

As shown, a roll 10 of thermoplastic material is supported adjacent oneend of the machine. A web 11 is advanced longitudinally of the machinepast successive stations. Heating heads 12 and 13 heat the web 11 sothat it may be formed into any desired shape. At the next station, acup-like member, generally designated C, is pressure formed in web 11 bya mandrel 14 adjacent one side of the web and pressure adjacent theother side. It is contemplated that vacuum forming may also be utilized,and the term pressure-formed should be taken as including pressureforming, vacuum forming, and other types of forming. Mandrel 14 moves inthe direction of arrows 15 between a forming position generallycontiguous to the web and a second position (shown in dashed lines)removed from the web so that the web may be intermittently advanced. Webadvancement is accomplished by gripper 16 which is reciprocated bypiston 17 in the direction of arrows 18.

While other shapes are contemplated, the cup-like container C ispreferably rectangular as best shown in FIGS. 2 and 3. As shown, thecontainer has a generally flat bottom 22 and side walls 23-26. The sideWalls advantageously slope uniformly upwardly from the bottom 22. Theupper ends of the side walls are preferably coplanar and define the openend of the container. An outwardly projecting flange extends outwardlyaround the periphery of the side walls and at the upper end thereof. Theoutwardly projecting flange advantageously includes an inner portion 28and an outer portion 29 stepped above the inner portion a preselecteddistance. The inner portion 28 is coplanar with the upper end of theside walls and extends a distance outwardly therefrom. The outer portion29 has its upper face at a level above the upper face of inner portion28 and defines a plane parallel thereto. As can be seen in the drawings,a series of containers C is advantageously formed in web 11 in such amanner that adjacent outer portions 29 are interconnected.

After the container C is formed in web 11, it is advanced to a thirdstation where an opening 30 is formed in the flange member. The openingis formed by means of a punch 32 and a die 34 (See FIG. 2) mounted atsaid third station. It is contemplated that the opening may also beformed at the aforedescribed forming station, if desired. Preferably,opening 30 is formed in the outer flange portion 29 and in theinterconnecting portion between two adjacent containers. As shown,opening 30 is more closely adjacent side wall 26 than side wall 24 for apurpose which will hereinafter become apparent.

At a fourth station, a preselected quantity of a product P is dispensedinto the container C. While the product P may be any type which may behandled and packaged, in accordance with the present invention it wouldbe a product advantageously packaged in a protective atmosphere such ascarbon dioxide, nitrogen, argon, active nitrogen, or the like.

Simultaneously with the above operation, a second roll of thermoplasticmaterial 40 is supported on the machine and a web 41 withdrawntherefrom. In similar fashion, the web 41 is heated by heating members42 and 43. An inner cover, generally designated I, is pressure-formed bymandrel '44. The web 41 is advanced to a cutting station where cutters45 accurately cut the inner cover I to its required shape. Preferably,the inner cover I is shaped to lie contiguous to the inner flangeportion 28 and span the open end of container C. The inner covers I aregripped by a reciprocating head 46 which deposits each inner cover on arespective container C which has been filled with product P.

In the embodiment illustrated, inner cover I includes a spanning portion52 extending adjacent the side walls 23-26 of container C and at a levelbelow the upper ends thereof. Walls 53-56 extend upwardly from spanningportion 52 and are tapered outwardly generally parallel to side walls23-26 of the container. The taper of side walls 53-56 advantageouslyprovides a self-centering action when the inner cover is placed inposition and allows the inner cover to nest in the position illustratedin the drawings with its walls 53-56 generally contiguous to side walls23-26. A peripheral portion 58 extends outwardly from walls 53-56 and isengaged with inner flange portion 28 of the container C. As illustrated,a channel 59 is preferably formed in Wall 56 and peripheral portion 58in the area of opening 30 to provide communication with the interior ofcontainer C. While channel 59 is herein illustrated as being formed ininner cover I, it may be formed in the container C as, for example, inside wall 26 and the flange member. The advantages of channel 59 willhereinafter become more apparent.

In some packages, inner cover I may be omitted. In such a case, innerflange portion 28 may also be omitted and the entire flange member maybe planar. The channel 59 is not required in such an arrangement;however, if desired, the channel is then advantageously formed in theflange member and extending from opening 30 to side wall 26.

A third roll 60 is supported on the apparatus, and a thin, flexiblesheet 61 is withdrawn therefrom. Sheet 61 is advantageously stretchableand adapted to be sealed to the flange member of container C along apreselected peripheral area. Preferably, compatible thermoplasticmaterials are selected for web 11 and sheet 61, and the sealing may beaccomplished by heat sealing. It should be understood, however, thatother materials may be utilized and that other sealing methods may beused. It is preferable, however, that sheet 61 which provides the covermember of the finished package, be flexible for a purpose hereinafter tobecome apparent. Sheet or cover member 61 is placed in juxtaposition tothe flange member, as shown, and the container C, inner cover I, andcover member 61 advanced to an evacuable chamber, generally designatedX, and illustrated in detail in FIGS. 4-6. At chamber X, the air isevacuated from the chamber and container C, a protective atmosphere of apreselected type is introduced through the opening 30 into the containerC, and the cover member 61 is thereafter hermetically sealed to theouter flange portion 29 and inwardly of the opening 30. The exactapparatus and the steps of the method will hereinafter be described indetail.

At this point, a plurality of scaled packages is interconnected in acontinuous web as illustrated in FIG. 1. The web of sealed packages isadvanced to another station 64 where the packages are cut from the webby cutters 65 and 66. The completed packages are deposited on a conveyor68, and the waste portion of the web is fed out of the machine andconveniently cut into small waste sections by cutters as at 69. Atcutting station 64, the continuously web is conveniently cut inside ofthe outer extremity of the seal area elfectuated at chamber X to insurethat the seal between cover member 61 and outer flange portion 29extends entirely to the edge. This provides a very neat package with noloose outer cover. If desired, a peel portion of any desired length maybe formed outwardly of the seal area in any convenient manner.

As explained above, vacuum packing has the disadvantage of collapsingthe package when it is exposed to atmospheric pressure. Additionally, acertain residue of air is necessarily left in the package, and this cancause some deterioration of certain products such as meat. The gas flushprinciple allows a protective atmosphere to be flowed into the package;however, in the past this has necessitated partially sealing the packageand introducing the protective atmosphere through a lancet or the likeextending into the container. In accordance with the present invention,it is desirable to reduce the residue of air in the container to aminimum, flow a protective atmosphere into the container, and thereafterhermetically seal the package in a single sealing operation. These stepsare advantageously performed at the evacuable chamber X illustrated inFIGS. 4-6.

In the embodiment illustrated, the evacuable chamber includes a lowermember 71, movable in a vertical direction by any convenient means. Inits upper position, shown in FIGS. 4-6, the lower member 71 engages withan upper member 72 to form a substantially air-tight enclosure. A gasket73 conveniently at the top of the lower member engages with peripheralpart 74 of the upper member 72 to insure that the enclosure thus formedis substantially gas-tight. As shown, the lower member 71 is formed witha lower cavity 78 shaped for receiving the containers C therein. Theupper member 72 describes an upper cavity 79 which is in communicationwith the lower cavity 78 via passage 76 in lower member 71, as shown inFIG. 4.

Disposed in the upper cavity 79 is a heat sealing head 82 havingprojecting parts 83 of a shape generally corresponding to the flangemember for sealing the cover member 61 thereto. Sealing head 82 ismovable between a position removed from the cover member, as shown inFIGS. 4 and 5, and a sealing position engaged with the cover member, asshown in FIG. 6. The sealing head may be heated in any convenientmanner; or may be adapted for pressure sealing if a pressure-sensitiveadhesive is utilized. Ultrasonic or high frequency sealing and othersealing methods may also be used, if desired. Sealing head 82 isconveniently provided with openings 84 as an aid in evacuating thecavities 78 and 79, If desired, sealing head 82 may be kept stationaryand lower member 71 moved upwardly for the sealing operation.

The cavities 78 and 79 can be placed in communication with theatmosphere or with a vacuum pump (not shown) by means of a valve 86connected to chamber outlet conduit 87, pump conduit 88, and atmosphereconduit 89.

In the operation of the device, the lower member 71 is lowered relativeto the upper member 72 and the container C, inner cover I, and covermember 61 are moved in the direction indicated by arrow g in FIGS. 1 and2. The container C is supported by a plate 92 (see FIG. 2) during theearly part of this movement, from which it is transferred to the chamberX. Lower member 71 is then moved upwardly by means not illustrated untilthe gasket 73 comes into contact with the upper member 72 or clamps theflange portion 29 and cover member 61 therebetween. It will be notedthat the opening, olfset toward side wall 26, is disposed inwardly ofsaid clamping.

Valve 86 is now operated so that conduit 88, which is connected to avacuum pump, is placed in communication with outlet conduit 87, and thepressure within the cavity 79 is reduced to a value below atmospheric.Moreover, since cavity 79 is communicated with cavity 78 by conduit 76,the pressure in this lower part is likewise reduced. The interior of thecontainer C'and the space between inner cover I and a cover member 61 islikewise reduced through flow of air through channel 59 and gaps as at93 (see FIG. 4) caused by the air pushing out and flexing the covermember 61 somewhat as a result of the pressure differential.Advantageously, a high vacuum is drawn; for example, around 27-29 inchesof mercury. When the desired amount of air has been evacuated, valve 66is moved to a closed position blocking any flow through conduit 87, asshown in FIG. 5.

As shown in FIGS. 5 and 6, lower member 71 is provided with a passage 95communicating with opening 30. A supply of protective atmosphere 96 isconnected to passageway 95 by means of a conduit 97. A pressureregulator 98 is provided to control the pressure of the protectiveatmosphere flowed into the chamber. A valve 99 is interposed in conduit97, and a timer 100 is conveniently provided to control the valvebetween on and 011 positions. When valve 99 is turned on, the protective atmosphere is allowed to flow through conduit 97, passageway 95 andopening 30. The force of this flowing gas is such to stretch covermember 61 slightly above the opening 30, and the gas flows into thecontainer C through the gap thereby provided and through channel 59.Since opening 30 is approximately at the center of the container C, theprotective atmosphere will flow first into the container and then, bydifferential pressure between the container and cover member, into thecavities 78 and 79. In this manner, an amount of the residue of air isadvantageously flushed into the cavities. Timer 100 is arranged to allowflow of gas over a suflicient period of time to allow the pressure inthe container and cavities to reach the pressure set on regulator 98. Inaccordance with the present invention, it is preferable that thispressure be approximately atmospheric so that the con tainer willneither bulge nor be collapsed when exposed to atmosphere. After thepressure in the container and cavities has reached the preselectedamount, timer 100 turns off valve 99. In some cases to conserve gas,valve 86 is opened to atmosphere while the pressure in the cavities issubatmospheric, but after the pressure in the container C has beenreturned approximately to atmospheric.

Sealing head 82 and lower member 71 are then moved relative to eachother by any convenient means. In this manner, projecting parts 83 ofsealing head 82 press the cover member 61 into contact with the outerflange portion 29, sealing the two together to provide a gas-tightpackage. In accordance with the present invention, it is necessary thatthe sealing area be inwardly of opening 30. The projecting part 83 isalso advantageously arranged to engage the portion of channel 59 formedin peripheral portion 58 and depress the channel into engagement withinner flange portion 28 as shown in FIG. 6. In this manner, at least aportion of the channel is ironed out during the sealing operation. Toaccomplish this, inner cover I is advantageously formed of a materialwhich will be ironed out by the sealing head. In one embodiment,polyvinyl chloride is used, and heat is applied during the sealingprocess. The application of heat to channel 59 causes it to resume itsoriginal, predeformed state. At the end of the sealing process, the head82 is returned to its upper position, valve 86 is operated to connectthe outlet conduit 87 to atmosphere conduit 89, and the lower member 71is lowered to allow the sealed package to be removed from the evacuablechamber X.

A method of packaging, as contemplated by the present invention,includes forming the cup-like container C having an out-turned flangemember at the upper end thereof. A predetermined quantity of the productP is deposited into the container, and cover member 61 placed injuxtaposition to the flange member for hermetically sealing theretoalong a preselected area having an inner seal line. As described above,opening 30 is formed, as by punching, in the flange member outwardly ofthe inner seal line. The container C and the cover member 61 are placedin the evacuable chamber X, and the cover member '61 is clamped to theouter flange member 29 outwardly of opening 30 and at two opposite sidesof the container. Preferably, at least one of the intermediate sides isleft unclamped to aid in the evacuation and refill of the chamber by theprotective atmosphere. The chamber is evacuated through a conduitcommunicating outwardly of the package, and the air in the package flowstherefrom between the flange member and cover member at the unclampedside of the package. A flow of protective atmosphere is introducedthrough opening 30,and said flow stretches the cover member 61 somewhatand the protective atmosphere passes into the container. The pressuredifferential then allows the protective atmosphere to flush the residuefrom the container as the protective atmosphere flows into the chambercavities between the flange member and cover member at the unclampedside. Thereafter, the cover member is hermetically sealed to the flangemember along the peripheral area to form a sealed package, and thepackage is removed from the evacuable chamber.

It is important to note that by the present invention the protectiveatmosphere is introduced directly into the package rather than merelyinto the evacuated chamber surrounding the package. This is particularlysignificant when a lighter-than-air gas, such as hydrogen, is utilized.

While a heavier-than-air gas such as carbon dioxide, would force theresidue upwardly and outwardly of the package, the opposite results whena lighter-than-air gas is used and the residue may tend to becometrapped. By causing flow from the container into the evacuated chamber,the protective atmosphere mixes with the residue air within thecontainer and carries the same outwardly into the chamber.

It is now deemed obvious that the present invention provides a usefulpackaging method and apparatus which has advantages of both vacuum andgas flush packaging. The protective atmosphere is directed into thepackage and therefrom into the chamber, and the present inventionaccomplishes this without the use of any apparatus extending into thepackage. Additionally, it can be seen that the sealing is advantageouslyaccomplished in a single operation.

The invention in its broader aspects is not limited to the specificsteps and apparatus shown and described, but departures may be madetherefrom without departing from the principles of the invention andwithout sacrific ing its chief advantages.

What is claimed is:

1. In a method of packaging including forming a cuplike container havingan out-turned flange member at the upper end thereof, depositing apredetermined quantity of a material to be packaged into the container,and positioning a cover member in juxtaposition to the flange member forsealing thereto along a preselected peripheral area which defines aninner seal line, the improvement comprising the steps of: forming afirst opening in one of said members outwardly of the inner seal line,placing said members in an evacuable chamber, holding the cover memberin juxtaposition to the flange member while maintaining an unsealedrelationship therebetween to provide communication between the containerand chamber, reducing the air pressure in the chamber by drawing avacuum through a second opening spaced from the first opening andcausing the air in the container to flow between the unsealed membersinto the chamber, introducing a protective atmosphere through said firstopening and against the opposite member and between said unsealedmembers into the container and therefrom into the chamber to flushresidue of air from the container, thereafter hermetically sealing thecover member to the flange member along said preselected peripheral areato form a sealed package having the protective atmosphere therein, andremoving the ackage from the chamber.

2. A method of making a sealed package having a protective atmospheretherein from two layers of packaging material, comprising the steps of:providing a first opening in one of said layers, placing said layers inan evacuable chamber, maintaining the layers in unsealed relationshipwhile clamping the layers together outwardly of the first opening and attwo opposite sides of the package and leaving at least one intermediateside unclamped, evacuating the chamber through a second openingoutwardly of the package and causing the air in the package to flowtherefrom between the layers at the unclamped side into the chamberthereby evacuating the package, introducing a flow of said protectiveatmosphere through the first opening and into the package and therefrominto the chamber between the layers at the unclamped side, thereafterhermetically sealing said layers together completely around theperiphery thereof and inwardly of the first opening, and removing thesealed package from the chamber.

3. In a method of packaging including forming a cuplike container havingan out-turned flange at the upper end thereof, depositing a material tobe packaged into the container, and positioning an outer cover injuxtaposition to the flange for sealing thereto, the improvementcomprising the steps of: forming the flange with inner and outerportions and with an opening in the outer portion, placing an innercover contiguous to the inner portion of the flange, forming a channelin one of said inner cover and inner flange portion in the area of theopening to communicate the interior of the container with the opening,placing the container and covers in an evacuable chamber, reducing thepressure in the chamber, introducing a pr tective atmosphere through theopening and channel into the container, hermetically sealing the outercover to the outer flange portion inwardly of the opening to provide asealed package having the protective atmosphere therein, and removingthe package from the chamber.

4. A method as set forth in claim 3 including ironing out at least aportion of the channel during the sealing step.

5. In a method of packaging including forming a cuplike container havingan out-turned flange member at the open end thereof, depositing amaterial to be packaged into the container, and positioning an outercover member in juxtaposition to the flange for sealing thereto, theimprovement comprising the steps of: placing an inner cover in positionoverlying the open end of the container and contiguous to an innerportion of the flange member, spacing at least a portion of the innercover away from the inner portion of the flange member at one side ofthe container to provide a flow channel into the interior of thecontainer, reducing the pressure in the container, introducing aprotective atmosphere between said members and through the flow channelinto the container, and thereafter hermetically sealing the outer covermember to the flange member outwardly of said inner portion thereof toprovide a sealed package having the protective atmospshere therein.

6. In a packaging apparatus including first forming means for forming acontainer having an outturned peripheral flange member with inner andouter portions at the open end thereof; means for depositing a quantityof a material to be packaged into the container; means for positioning acover member overlying the container and in juxtaposition to the flangemember; an exacuable chamber including upper and lower enclosing meansmovable relative to each other between one position to provide asubstantially gas-tight chamber and a second position removed from theone position to provide an opening for entry of the container and covermember, said upper and lower enclosing means operative in the oneposition to support the container and cover member; and meanscommunicating with the chamber outwardly of the container for reducingthe pressure in the chamber and container to a value below atmospheric;the improvement comprismg:

means for forming an opening in the outer portion of the flange memberprior to entry of the container into the chamber;

second forming means for forming an inner cover for spanning the openend of the container and supported by the inner portion of the flangemember;

means for placing the inner cover in a position contiguous to the innerportion of the flange member prior to the cover member being juxtaposedto the flange member;

one of the first and second forming means operative to form a channelfor communicating the flange opening with the interior of the container;

means communicating with the flange opening and terminating at theunderside of the flange for introducing a protective atmosphere throughthe flange opening and channel into the container to return the pressurein the container and chamber generally to atmospheric;

a sealing head disposed in the chamber above the cover member and havinga lower portion shaped for hermetically sealing the cover member to theflange member and inwardly of the flange opening; and

means for moving the sealing head and container relative to each otherto engage the sealing head with the cover member after the container andchamber have been generally refilled with the protective atmosphere.

7. A packaging apparatus including:

first forming means for forming a container having at the open endthereof an out-turned peripheral flange with inner and outer portions;

second forming means for forming an inner cover for spanning the openend of the container;

means for positioning the inner cover contiguous to the inner portion ofthe flange;

one of the first and second forming means being operative to form ashape that disposes at least a portion of the inner cover away from theinner portion of the flange when positioned by the last-mentioned meansto provide communication with the interior of the container;

means for positioning an outer cover overlying the container and innercover and in juxtaposition to the outer portion of the flange;

means for introducing a protective atmosphere between 9 10 the innercover and flange member and into the con- 3,343,332 9/ 1967 Mahalfy eta1. tainer; and 3,283,469 11/1966 McBrady et a1. a sealing head forhermetically sealing the outer cover 2,888,787 6/1959 Cloud 5322 to theouter portion of the flange to complete a sealed package having theprotective atmosphere 5 THERON ECONDONPrimary Examiner therein.

References Cited H. M. CULVER, Assistant Examiner UNITED STATES PATENTSCL X'R' 3,196,590 7/1965 Ollier et a1. 10 53-112, 373

3,347,011 10/1967 Lovas et a1.

